Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

740
FXUS63 KLOT 011133
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
633 AM CDT Wed Apr 1 2026

.KEY MESSAGES...

- Windy Thursday with southerly winds gusting 40-45 mph.

- Strong to severe thunderstorm threat (level 2 out of 5)
  ahead of a cold front Thursday afternoon/evening.

- An active pattern will continue through Saturday with periods
  of showers and thunderstorms.

&&

.DISCUSSION...
Issued at 304 AM CDT Wed Apr 1 2026

Through Friday:

An active weather pattern is expected to continue through
Saturday before a period of quieter weather is anticipated into
early next week. Of particular interest in this pattern, is the
threat for another round of severe thunderstorms, particularly
Thursday afternoon into the evening.

The surface cold front from yesterday has settled into southern
parts of IL. It will stall in this region for a period today
before lifting back northward tonight into Thursday morning in
association with the next quickly developing Plains cyclone. In
spite of the southern placement of the surface front, warm air
advection aloft over this frontal boundary is expected to
continue to generate showers and some non-severe thunderstorms
across a west-to-east corridor from Missouri eastward across
central IL and IN. It appears the more persistent showers today
will occur along and south of I-80 this morning in advance of an
approaching low amplitude impulse tracking eastward through the
Midwest. Shower coverage should then be on a decreasing trend
through the afternoon.

We cannot rule out a few showers making there way as far north
as the Chicago metro area later this morning into the early
afternoon. However, much of the area north of I-80 should see a
good amount of dry time today, albeit with cloudy and cool
conditions. Blustery east-northeasterly winds, gusting up around
30 mph will promote a much cooler day, particularly along and
near the Lake Michigan shore, where temperatures today will
remain in the low 40s. Farther inland, conditions won`t be much
better, with cloudy and breezy weather only supporting
temperatures into the mid to perhaps upper 40s well south and
inland.

Attention quickly turns to the next shortwave trough, currently
noted in the water vapor imagery moving onshore across
California. This wave will eject eastward across the Four
Corners region of the Desert Southwest through the day, before
transversing the CO Rockies and inducing lee cyclogenesis over
the central Plains this evening. Thereafter, the parent surface
cyclone is favored to track northeastward across the Mid-
Missouri Valley on Thursday, then into the Upper Great Lakes
late Thursday evening and night. As it does, the remnant frontal
boundary, stalling today across downstate IL, will shift back
northward across the area as a warm front Thursday morning,
setting the stage to a return to more active weather locally
tonight and on Thursday.

Waves of showers and embedded thunderstorms are expected to
develop tonight north of the surface warm front as a
strengthening southerly low-level jet ramps up moisture
advection over the frontal boundary. This activity is expected
to overspread our area for a period tonight into early Thursday
morning. Very low clouds and possibly even some fog may also
briefly develop north of the warm frontal boundary for a period
early Thursday morning. Once this boundary finally shifts north
of the area (may become briefly hung up along the northeastern
IL lake shore through late morning or early afternoon)
developing gusty south winds (potentially gusting to or even a
bit in excess of 40 mph) will push temperatures back to 60s and
70s as surface dewpoints surge into the lower 60s.

The main concern on Thursday continues to revolve around the
threat for severe thunderstorms, particularly in the afternoon
and evening as the potent spring cyclone tracks northeastward
across northeastern IA into WI. As is typical with such a system
this time of year, deep layer low- to mid-level south-
southwesterly flow in excess 60 kt will result in very
impressive kinematics across the area. It also appears that the
very moist warm sector (low 60s dewpoints) will foster ample
afternoon destabilization, despite the likely presence of
extensive cloud cover and even ongoing rounds of morning and
early afternoon convection. This initial convective activity on
Thursday may end up being the remnants of overnight convection
to our southwest. Assuming adequate destabilization is able to
occur in advance of the cold front and area of low pressure
shifting into northeastern IA, conditions will be favorable for
severe thunderstorms, including a threat of tornadoes.
Accordingly, the SPC conditions to highlight our area in a level 1
out of 5 severe risk for Thursday. Expect the threat of storms to
persist with the cold front through early to mid Thursday
evening, before the activity wanes with the cold frontal passage.
In addition to the severe threat, we will also have to keep an eye
on the threat for any localized flooding from the heavy rainfall
expected to accompany these storms.

In the wake of Thursday`s system, we do look to briefly dry out
late Thursday night into early Friday. However, another storm
system will be quickly developing and approaching the area later
in the day Friday, with more heavy rain producing showers and
storms expected into Saturday morning.

KJB


Friday Night through Tuesday:

The upper trough/low that currently sits off the coast of the
Pacific Northwest is forecast to be ejecting into the central
Plains by Friday evening. As it does so, a surface low is
expected to be developing in eastern KS and western MO that will
then begin to lift towards the Mississippi Valley Friday night
into Saturday. The approaching surface low is expected to lift
the stalled frontal boundary forecast to be in central IL/IN
back northward as yet another warm front bringing with it an
additional period of showers and thunderstorms. However, the
projected track of the surface low from northern MO to southern
WI Friday night looks to limit the northward extent of the warm
front before the system`s cold front is ushered through northern
IL and northwest IN early Saturday morning. While this likely
won`t do much to limit the coverage of rain, it may limit the
amount of instability that is able to build into the area and
thus make the coverage of thunderstorms a bit less especially
for further north in our CWA. That said, if sufficient
instability can materialize Friday night, then a localized
strong to severe storm threat could develop given the 40-45 kts
of shear forecast to be present.

Regardless of the storm coverage/intensity, widespread rain is
likely Friday night through Saturday as this system moves
through. While the system is forecast to be rather progressive,
the nearly continuous rounds of rainfall leading up to this
event will make conditions favorable for some localized flooding
issues before rain ends Saturday evening. Outside of the rain,
temperatures on Saturday are also expected to be cooling through
the day in the wake of the cold front. So be prepared for the
warmest temperatures to occur early before they dip into the 40s
by Saturday evening.

In the wake of this system, a period of drier weather is
expected to close out the weekend as a surface high moves into
the Mississippi Valley. However, the upper trough is expected to
stall over the Great Lakes which will result in nearly constant
northwest flow resulting in seasonably cool high temperatures
in the 40s to lower 50s for Sunday and again on Monday.

The upper trough is forecast to start pushing east of the Great
Lakes on Monday as an upper ridge builds over the central
CONUS. As a parting gift a final shortwave is progged to round
the backside of the trough Monday night which could bring us one
more period of rain showers during this timeframe, That said,
there is a lot of variability in guidance as to how much
moisture will be available Monday night as the wave moves
through so there is a chance that the rain avoids northern IL
and northwest IN all together. For now though will advertise a
20-40% chance for rain. After Monday night, the upper ridge will
be moving into the Great Lakes which will promote dry
conditions for the middle of next week with temperatures
moderating towards more seasonable values in the mid to upper
50s.

Yack

&&

.AVIATION /12Z TAFS THROUGH 18Z THURSDAY/...
Issued at 633 AM CDT Wed Apr 1 2026

Forecast concerns for the terminals...

- Off and on drizzle/sprinkles through this afternoon with a
  20-30% chance of showers.

- Widespread rain showers and embedded thunderstorms this
  evening and overnight which could result in IFR ceilings and
  visibilities.

- Breezy northeast winds gusting around 20-25 kt through tonight
  with MVFR ceilings. Winds become southwesterly Thursday
  morning with gusts up to 25-30 kts.


A broad area of showers and embedded thunderstorms continues to
drift across northern MO and central IL/IN this morning with
sprinkles and drizzle being noted on the northern fringes of the
precipitation band. While periods of sprinkles/drizzle could
move across the terminals through this afternoon, it seems the
better chance for any true showers will hold off until late this
afternoon and evening (20-30% chance). The best coverage of rain
will occur this evening as the frontal zone in central IL/IN
lifts back north as a warm front. Once this rain arrives it is
expected to persist through tonight with chances for embedded
thunderstorms at times especially after midnight (20% chance).
The more convective showers/storms after midnight may also
result in periods of IFR ceilings and visibilities through early
Thursday morning.

Outside of the rain, winds will remain breezy out of the
northeast today with gusts around 20-25 kts. Ceilings will also
continue to lower back to MVFR over the next couple of hours
where they are expected to remain through the rest of the
forecast period. The exception, however, will be at RFD where
lower-end VFR conditions look to prevail through this
afternoon.

Heading into Thursday, it appears that any showers/storms
overnight should gradually diminish by mid-morning before the
main cold front moves through Thursday afternoon and brings
additional chances for showers and thunderstorms. However,
confidence on whether or not rain actually stops is low and thus
have maintained a VCSH through the end of the 30-hour TAFs.
Furthermore, ceilings may also attempt to rise if rain stops
Thursday morning but this too is low confidence. Regardless,
winds will become more southeasterly Thursday morning with gusts
increasing into the 25-30 kt range.

Yack

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 4 AM CDT Friday for the IL and IN
     nearshore waters.

&&

$$

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